16   How instruments are to be written and stamped

(1)  Every instrument written on stamped material is to be written in such manner, and every instrument partly or wholly written before being stamped is to be so stamped, that the stamp may appear on the face of the instrument, and cannot be used for or applied to any other instrument written on the same piece of material.

(2)  If more than one instrument is written on the same piece of material, every one of such instruments is to be separately and distinctly stamped with the duty with which it is chargeable.